Railway traffic controlling apparatus



Sept. 9, 1958 D, D, HUFFMAN ETAL l 2,851,589

RAILWAY frRAFFIC CONTROLLING APPARATUS Filed Aug. 14. 1956 IN VEN TORS i@ Hg A.. an .n dy w 2,851,589 nativ/AY Triassic coNrRoLrlNo APPARATUS Donald D. Huffman, Pittsburgh, Pa., and .lohn R. George, Concord, Mass., assignors to Westinghouse Air Brake Company, Wilmerding, Pa., a corporation of Penney!l vanta Application August 14, 1956, Serial No. 603,960

7 Claims. (Cl. 246-46) Our invention relates to railway trailc controlling apparatus, and more particularly to the type known as tratc locking apparatus, which requires joint action by operators at two diferent control stations for manually controlling tralic movements in both directions over a stretch of railway track.

When trafc is to be operated in either direction over a stretch of railway track extending between two loca tions, trac locking apparatus is provided which commonly includes a traffic locking circuit controlled jointly by an operator at each end of the stretch of railway track. Such a traic locking circuit is adapted to prevent the manipulation of trac governing signal levers for changing the direction of traic on the stretch of track while it is occupied or while a signal indication is displayed for a train to proceed into that stretch. Quite commonly, this tratc locking circuit extends between two attended interlocking stations or towers and may be controlled by traic levers included in the respective interlocking machines. In many cases, these traffic levers are of the mechanically locked type, which may be unlocked to change the direction of trac only by coordination of the eiorts of the two operators when certain conditions exist which make it safe to reverse the traic direction. With such an existing installation, it frequently becomes necessary or appropriate for the interlocking at one end to be replaced by a more modern allfrelay or remotely controlled type interlocking. Either of these two types of interlockings is, in etfect, of the free-lever type in which the tratlic lever itself is not locked and is free to be moved between its extreme positions at any time. Also,

as part of the modernization program, it may be desirable to use the tratlic locking circuit, that is, the control channel extending between the two locations, which was previously used as part of the mechanically locked system.

This re-use of the traic locking circuit provides economy i of both time and apparatus. This existing circuit may be of a two wire, double-break type or of a single wire,

single-break type with a common battery wire.

Regardless of the type of control channel or locking circuit used, the final circuit arrangement for controlling the traic direction between the two locations must include the proper safety features. As one safety feature which must be provided, the manipulation of the free trafc lever or control means at any time must not adversely affect any signal which has been cleared to permit tratlc to move into the stretch of main track between the two locations. Also, the traffic locking circuit must include the usual detector arrangement, which will indicate and prevent operation of the circuit when a train is occupying any portion of the stretch or when route locking has been established for a train approaching the stretch of track. In the event that the trafc locking circuit is interrupted or the power source is temporarily lost, another safety feature provides that the apparatus must be restorable to its original condition solely by the efforts ofthe operators. `In other Iwords, in the event .of this. type ofl'failureyit Ashould-.not be necessaryato call a Patented Sept. 9, 1958 Vice maintainer in order to restore the apparatus to its original condition.

Accordingly, it is an object of our invention to provide an improved form of trac controlling apparatus.

Another object of our invention is to provide an improved form of traffic controlling apparatus embodying a traffic control means of the free lever type at one location.

A further object of our invention is an improved traic control apparatus in which the relay operation is the equivalent of a mechanically locked tratic lever.

Still another object of our invention is an improved traic control circuit arrangement by which a mechanically locked tratlic lever may be replaced by a free lever with a minimum amount of change in the existing traffic locking circuit.

A still further object of our invention is to provide an improved trafc control arrangement which may be restored to normal by the operator, if the locking circuit or the power supply is inadvertently interrupted.

Another object of our invention is an improved tratlic control arrangement embodying a free type tratlc lever at one location in which either tratlc lever may be moved to the equivalent indicating position and not interfere with any signal cleared to permit a train movement into the controlled stretch of track.

Still another object of our invention is the provision of novel and improved means for trahie locking between two locations, specifically between two interlockings at least one of which is of the all-relay or remotely controlled type.

Other objects, features, and advantages of our invention will become obvious as the specification progresses.

ln practicing our invention, the mechanically locked traffic lever remains in service at the end of the trac locking circuit at which the interlocking apparatus is not to be renewed. At the opposite end of the stretch of track, the locked lever is replaced by a free type trafc lever which is part of an all-relay or remotely controlled interlocking. At this end of the trailic locking circuit, relay operation is provided which is the equivalent of the mechanical locking formerly in service. Each eX- treme position of the free tratlc lever is repeated by a relay which checks that the opposite lever repeater relay is released. In addition, a traftic stick relay means is provided, which consists of a relay, or a relay position, for each direction of trac. In either case, the operation of one relay, or of a single relay to a first position, establishes tratic in one direction. Operation of the other relay, or of the single relay to its opposite position, establishes trafc in the opposite direction. The traic stick relay means is controlled by the corresponding lever repeater relay and by one of two tralic locking relays provided. The control circuits for the signals at this end of the stretch of track are controlled by this stick relay means.

Our invention further retains the traffic locking circuit or channel formerly in service, including the usual track occupancy and route locking detection in order to provide the necessary safety checks. At the end of the trac circuit at which the modernization occurs, that is, at which the free trac lever is used, tratlic locking relays are inserted in the line circuit, one for the normal and one for the reverse direction of trathc. These relays are controlled not only by energy from the opposite end of the stretch but by the trac stick relays and by the position of the traffic lever through its repeater relays. Finally, the energization of the mechanical lock, to release the mechanically locked lever, is accomplished over the trailic locking circuit byl the reverse tratlic stick relay positionand by the normal lever repeater relay released. In addition, the mechanically locked lever must be in an indicating or locking position, as is usual for energizing the electric lock for these levers.

We shall now describe two forms of apparatus cmbodying our invention and thereafter point out the novel features thereof in the appended claims.

Referring now to the drawings,

Fig. l is a diagrammatic showing of one form of trafiic controlling apparatus embodying the features of our invention.

Fig. 2 of the drawings is a partial showing, based on Fig. l, of a second form bf traic controlling apparatus also embodying our invention.

In each of the drawings, similar reference characters refer to similar parts of the apparatus.

Referring novi to Fig. l of the drawings, there is shown across the top of this drawing, by a conventional single line representation, a stretch of railway track between two spaced locations A and B. At each of these locations there is an interlocking. The interlocking at location A is oi a simple nature consisting only of a single crossover between the stretch of track shown and a second track partially shown in the drawing. This crossover includes the two switches KW and .lV/A. It may be considered that this second track partially shown converges at location A with the main track and then extends as a second track from location A to location B. However, for purposes of the description of the apparatus of our invention, this second track is not necessary and thus is not shown. The interlocking at location B is more extensive in nature and is partially shown to consist of a diverging track entered over switch 5W in its reverse position and a crossover including switches 'IW and FIWA leading to a second stretch of track. it may be considered that the interlocking at location B includes other switches and Crossovers and wayside signals and that this location is now controlled, as a result of a modernization program, by an all-relay type interlocking, which has replaced an older mechanical style interlocking. However, because of the simplicity ol the interlocking at location A, the mechanical type control means at this location remains in service. 'I'he stretch of track between locations A and B is used for trafic in both directions. The normal direction of trac is from B to A, that is, in the westbound direction. As previously mentioned, a second track exists between these locations which normally is used for eastbound tra However, on occasion the stretch of track shown is und for the movement of eastbound trains from A to 'l'.

The stretch of track between locations A and B divided into sections in the usual manner by insole joints, shown as heavy lines at right angles to the c nventional single line track symbol. These track sections are designated by the reference characters 1T, 3T, and 5T. Section 1T includes a short portion of the track in the vicinity of location A and includes switch .uw or the crossover at that location. Section 5T is illustrative only of a detector section in the interlocking at location B and as shown includes a short portion of the main track, switch 5W, and switch 7W of the crossover. Section 3T includes the remainder of the stretch of track between these two locations. lt is to be understood, however, that this portion of the track may be divided. into more than one track section, but for simplicity the single section only is here shown.

Each of these sections of track is provided with a normally energized track circuit, which includes a source of energy, the rails of the track section, and a track relay. For simplicity, the track circuits are of the direct current, neutral type and are shown conventionally in keeping with the single line showing of the track itself. For example, section 1T is provided with a battery ITE, connected to the rails at the left end of the section, and with a track relay lTPt, which is shown in a conventional manner connected to the rails at the opposite end of the track section. Relay lTR is normally energized, that is, is energized when no portion of a train is occupying any part of track section 1T. Section 3T is provided with a battery 3T3 shown connected at the east end of the section and with a track relay 3TR shown connected to the rails at the western end of the section. Track relay STR also is normally energized when the section is unoccupied.

While section 5T will also be provided with a track circuit for occupancy detection, this track circuit and the corresponding track relay are not shown since this section will also have associated therewith a route and detector locking relay such as the relay 5WS. Relay 5l-VS will combine the functions of occupancy detection and route locking detection for section 5T, and may be used, as will be discussed later, for the purpose of safety checks in the traffic locking circuit. The actual ccntrol circuits tor relay SWS are not shown as they form no part oi our invention, but it may be considered that this relay is energized when section 5T is unoccup i by a train and is not included in any route established through the interlocking at location B.

The exit relay 6X8 is also associated with the interlocking apparatus at location B, and is used specifically to indicate, when energized, that a route has been established through the interlocking which exits or departs from the interlocking limits at signal 6R, which, as will be discussed later, is the `signal governing train entry into the .interlocking limits. In other words, when relay 6XS is energized, a route has been established which includes section 5T and through which a train will depart in a westbound direction passing signal 6R. The utility of this relay in the circuits of our invention will appear hereinafter during the description of the operation.

It is pointed out at this time that a suitable source of direct current energy of low voltage is provided at each location. This power source preferably is a battery of the proper voltage and capacity to provide control current for the locally energized relays and other apparatus.

For simplicity, these batteries are not shown, but at each location their positive and negative terminals are indicated by the conventional reference characters B and N, respectively. In addition, a power supply is required at each location for the traffic locking circuit to be discussed hereinafter. Again these power sources are preferably a battery of proper voltage and capacity, but, for simplicity, are not shown. The positive and negative terminals of these batteries are indicated at each location by the reference characters LB and LN, respectively. It is also to be noted that, in such an installation, the negative terminals of these line batteries will be connected together by a common wire, which likewise, for simplicity, is not shown.

In order to provide additional safety factors in case of an accidental cross or ground which establishes incorrect connections between the various battery terminals, certain of the relays provided in the circuit arrangement shown are of the biased type. Each of these relays is so indicated by an arrow within the symbol for the winding of the relay. The operation of these biased relays is such that when current flows through the relay winding in the direction of the arrow, the relays arc properly energized to pick up their armatures closing front ccntacts. However, when no current is tlowing in the relay winding, or if current ows through the winding in the direction opposite to the arrow, the relays are deenergized or are improperly energized, so that their armatures remain released with back contacts closed. As an example, attention is directed to the relay SNLP, in Fig. l, which is of the biased type. In Fig. 2, the relay SFS, which will be discussed later, is of the magnetic stick type having a double winding. In this type of relay, when current ows through either or both windings in the direction of the arrow shown in the relay winding symbol,

assises type, current is considered to flow from the positive to the negative terminal of the battery supplying energy to that relay.

Each of the locations A and B is provided with a trac control lever, the levers 1V and 5V, respectively. Lever 1V at location A is of the mechanically locked type, and is manually operable between the two extreme positions N and R representing, respectively, the normal and reverse traic directions. This lever is also operable to two corresponding intermediate indicating or locking positions B and D. Lever 1V is provided with a lock comprising the locking segment 11, which is mechanically operated by lever 1V, and with a lock magnet 1M, which controls a locking dog 12. When magnet 1M is deenergized, locking dog 12 engages a projection 13 on segment 11, if lever 1V is moved to either locking position B or D. The locking dog 12 thus prevents the movement of lever 1V from either of its extreme positions to the other eXtreme position until magnet 1M becomes energized.

Lever 1V operates a plurality of contacts each of which is represented by a circle in which is placed one or two reference characters corresponding to the positions of the lever at which the corresponding contact is closed. Of the two contacts shown, contact 14 is closed only when lever 1V is in its normal or N position, as is indicated by the letter N inside the symbol for the contact. Correspondingly, contact 15, as indicated by the symbol BD inside the circle, is closed when lever 1V is in either position B or position D or at any point in the movement between these two locking positions. A set of contacts 16 is also asscoiated with lever 1V. These contacts are controlled by the operation of the spring latch associated with the handle of lever 1V. In other words, when the handle is grasped and the spring latch is released, contacts 16 are closed to complete the circuit through them. This spring latch, it is to be noted, is not associated or part of the electric or mechanical locking device, but is merely to prevent unintentionally moving lever 1V from one position to another.

Traic lever 5V at location B is of the free lever type, that is, it has no mechanical lock associated therewith, and may at any time be moved between its extreme positions N and R. This lever operates two contacts designated by the reference characters 17 and 18, which -are closed, respectively, when the lever is in its normal position and in its reverse position. Lever 5V also has associated therewith a push button type contact 19, which is normally open. This contact may, if so desired, be spring biased to return to its open position when pressure is released. Preferably, lever 5V is of the push-turn type, that is, contact 19 is closed each time the lever is operated between its extreme positions.

Wayside signals are provided at locations A and B to govern the movement of trains into or out of the stretch of track between these locations. A location A, signal 2R governs the movements of trains traveling in the eastbound direction into the stretch of track shown, that is, through section 1T into section 3T. Correspondingly, at location B, signals 6L govern the movement of westbound trains out of the interlocking into the stretch of track, as represented by section 3T. Such trains may move according to the indication displayed on any one of the signals 6LA, dLB, or GLC, depending upon the route established for that train. The signals 2L and 6R govern movement of trains out of section 3T in the corresponding direction, but the control of these signals is not involved in the system of our invention. The levers 2V and 6V at locations A and B, respectively, provide a manually operable means to control the signals having the corresponding numbers. Each of these levers has three positions, a center or normal position N which the lever occupies when signals controlled thereby are all at the stop position. Each lever has a left-hand or L position in which circuits are completed to provide the control of the westbound or L signal associated therewith. The' third position, the right-hand or R position, correspondingly establishes circuits for the control of the eastbound or R signals at the corresponding location. Lever 6V is of the free lever type, and may be moved to any one ofits three positions at any time by the operator. However, lever 2V is of the mechanical lock type and is interlocked with trailic lever 1V, as is indicated by the dotted line 20. This interlock arrangement is such that, with switch 1W normal, lever 2V cannot be moved from its normal poistion to its R position unless traffic lever 1V occupies its reverse or R position. Correspondingl-y, once the lever ZV has been moved to its R position with lever 1V in its R position, the latter lever cannot be moved from the R position as long as lever 2V occupies its right-hand position. Thus' signal 2R cannot be cleared to permit a train to move into section 3T unless the traic direction has been established in the eastbound direction. y

At location B, in addition to relays SWS and 6X8 previously discussed, the circuit arrangement of our invention includes other relays. Two lever repeater relays SNLP and SRLP are provided to repeat the positions of traffic lever 5V. Normal lever repeater relay SNL? is energized, when lever 5V is in its normal position, by the circuit traced from terminal B through contact 1'7 of lever 5V, back contact 2l of relay SRLP, and the winding oi relay iNLP to terminal N. Reverse lever repeater relay SRLP is energized by a circuit extending from terminal B through Contact 13 of lever 5V, closed only with the lever in its R position, back contact 22. of relay 6X8, back Contact 23 of relay SNLP, and the winding of relay RLP to terminal N. This latter circuit includes back contact 22 of relay 6X5 to check that a route has not been established which will permit a train to leave the interlocking at signal 6R in a westbound direction. This check is necessary since lever 5V is ot the free movement type, so that it can be moved to its reverse position at any time by the operator. If a route has been established such that relay dXS is picked up, it is undesirable to energize relay SRLP under these conditions.

ln addition our invention provides, as shown in Fig. l, a pair of traic stick relays SNFS and SRFS for the normal and reverse directions of traffic, respectively. The final pair of relays provided by our invention are the normal traic locking'relay SNFL and the reverse tra'lc locking relay RFL, which will be discussed shortly. Normal tratlic stick relay SNFS is provided with an energizing circuit which includes front contact 24 of relay RFL, front Contact 2S of relay SNLP, and the winding of relay SNFS. When traic is established in normal direction, this relay is held energized over a stick circuit, which is traced from terminal B over back contact Z6 of reverse trailic stick relay SRFS, front f contact 27, and the winding of relay NFS to terminal N.

Relay 5RFS is provided with an energizing circuit which may be traced from terminal B at front Contact 23 of relay SNFL over front contact 29 of relay SRLP and' the winding of relay SRFS to terminal N. A stick circuit for this latter relay includes back Contact 31 of relay SNFSand front contact 32 of relay SRFS.

The traffic locking relays are inserted in the trac locking circuit, which extends between location A and location B. These relays are energized over this channel by the line batteries. For example, with normal traic direction established, relay SNFL is energized by a circuit which is traced from terminal LB at location A over contact 14 of lever 1V, Vfront contact 33 of track relay 1TR, front Contact 34 of track relay STR, front contact 35 of relay SWS, front contact 36 of relay SNFS, and

ythe winding of relay 'NFL to terminal LN at location B.

It is to be remembered, of course, that the terminals LN at the two locations are tied together by a common connection, which is not shown in the drawings. The reverse traffic locking relay SRFL is at times energized over a similar circuit, which is identical up to front contact 35 of relay SWS, and thence is traced over back Contact 36 of relay SNFS, front contact 37 of relay SNLP, and the winding of relay 5RFL to terminal LN. The lock magnet 1M at location A is also at times energized over this same tratiic locking circuit. The actual energizing circuit is traced from terminal LB at back contact 37 of relay SNLP at location B over back contact 36 of relay SNFS, front contacts 35, 34, and 33 of relays SWS, STR, and llTR, respectively, contact 15 of lever 1V, and the winding of lock magnet 1M to terminal LN at location A. The utility of this particular circuit will appear hereinafter during the discussion of the operation of the apparatus.

Each location also includes a signaling relay designated by the reference Z prer'ixed by a number corresponding to the tratiic lever. Each location is also provided with a signaling lamp ck and a buzzer BZ, these reference characters likewise being prefixed by a number corresponding to the tratlic lever at that location. These devices are energized or operated by simple circuits which will be discussed in detail with the operation of the apparatus.

We shall now discuss the operation of the circuit lill a change the direction of the established traflic between the locations A and B. As shown in Fig. l, the apparatus is in its normal condition, that is, it is in the condition when traffic is established in the predominant westbound direction. Also, no train is occupying any portion of the stretch of track and no routes' are established through the interlocking `at location B. Under these conditions, lever 2V cannot be moved to clear signal 2R, since trailic lever 1V is in its normal position, and

the signal lever is interlocked to prevent its movement to its R position. However, if desired, signal 6L can be cleared by the operator to authorize `a westbound train movement through section 3T. In other words, since lever 6V is of the free-movement type, it can be moved to its left-hand position to provide energy to the control circuit or'signal 6L. Under these conditions, this circuit includes tront contact 38 of relay SNFS, which is picked up'at this time, and Contact 39 of lever 6V, which is closed only when the lever occupies its L position.

It is now assumed that the operator at location A desires to reverse the direction of trahie through the stretch of railway track in order that he may clear signal ZRA to authorize a train movement eastbound through section 3T. The initial action of operator A is to operate the spring latch associated with lever 1V, retaining the lever in its N position. The closing of contact 16 completes an obvious circuit to energize signaling relay llZ. The closing of front contact di) of relay 1Z completes a circuit from terminal LB at location A through contact 16 of lever 1V, front contact 40 of relay 1Z, back contact 41 of relay 5Z at location B, and the winding of buzzer SBZ and the lamp Sek in multiple to terminal LN. This causes the buzzer to sound and the lamp to light to signal the operator at B of the request for a change in traiiic direction. Operator A then releases the spring latch, so that contact 16 `Opens to interrupt the energizing circuit for the buzzer and lamp at location B. If this request lits the plan of train disseurent of our invention it provides means to and buzzer indications cease, answers this request for traiic direction change by moving lever 5V from its normal toits reverse position. This action also closes push-button contact 19,` since lever 5V is assumed to be of the push-turn type. The closing of contact 19 completes an obvious circuit for energizing signaling relay SZ. This relay picks up, and the closing of its front contact 41l completes a circuit, which also includes contact 19 and back contact 40 of relay 1Z, to energize the buzzer lBZ and the indication lamp lek at location A. Operator A, upon receiving these indications, moves lever' from its normal position to the normal locking or indicating position B.

Meanwhile, the opening of contact 17 of lever 5V has interrupted the circuit for relay SNLP, and this relay, thus decuergized, releases. Assuming for purposes of the discussion that back contact 22 of relay 6X8 is closed to signify that no route with an exit at signal 6R is established, the closing of contact 18 of lever SV and back contact 23 of relay SNLP completes the previously traced energizing circuit for reverse lever repeater relay 5RLP. At this time, if relay SNFL is picked up, signifying that traic is locked in the normal direction, the closing of front contact 29 of relay SRLP completes the circuit for energizing relay SRFS, and this latter relay picks up at this time. The opening of back contact 26 of relay SRFS interrupts the stick circuit for relay SNFS, which then releases, closing its back contact 31 to complete the stick circuit for relay SRFS, this latter circuit also-including front contact 32 of the latter relay. In initiating this change of traiic direction, the non-occupancy of the stretch of track and the absence o route locking is checked by relay SNFL being energized and picked up, while the absence of any established route into section 3T from location B is checked when relay SRLP becomes energized. Thus, between these two relays, a complete check is made before the reverse traffic stick relay SRFS is energized. Relay SNFL is made slightly slow release by the resistor connected in multiple with the relay winding to bridge the open circuit time occurring between the opening of front contact 36 of relay SNFS, in the circuit for relay SNFL, and the closing of back contact 31 in the stick circuit for relay SRFS.' This assures that relay SRFS picks up and holds up during this action.

A circuit is now complete for energizing the lock magnet 1M, this circuit including back contacts 37 and 36 of relays SNLP and SNFS, respectively, front contacts 35, 34, and 33 of relays 5WS, STR, and 1TR, respectively, contact 15 of lever 1V, which is now closed with this lever in its B position. With lock magnet 1M energized, the locking dog 12 is picked up so that it no longer engages projection 13 on the locking segment 11, and the operator at A is now able to complete the movement of lever 1V through position D to the extreme rcverse position R. As soon as the lever is moved beyoud its reverse indicating position D, lock magnet 1M is deenergized by the interruption of its circuit `at contact 15.

With lever 1V in its reverse position, the signal lever 2V is unlocked and may now be moved to its R position to clear signal ZRA to authorize a train movement in the eastbound direction into section 3T. In other words, the traffic direction reversal is now complete. Energy is now supplied to the traffic locking circuit from location B over back contact 37 of relay SNLP, although the circuit for the lock magnet 1M is `at present interrupted at contact 15 of lever 1V. With lever 2V in its R position, energy is supplied over contact 42 of this lever, which is closed only when it occupies this position, to the control circuits for signal 2R.

With lever 2V in its right-hand or R position, tratiic lever 1V cannot now be returned to its normal position even though lock magnet 1M can be energized. This locking is accomplished through the mechanical interassunsev lock previously discussed and indicated by thel dotted line 2S. When the train has entered thestretch of track so that one or more of the relays ITR, STR, and SWS are deenergized, the lock magnet 1M cannot then be energized even though lever 1V is moved to the reverse indicating position D to otherwise complete the traffic locking circuit. It is also to be noted that if lever SV at location B is moved to its normal position, this cannot affect the reverse tralic direction already established nor can this movement aifect the indication displayed by signal 2R under the reverse trac condition.

It is now assumed that it is desired to return the direction of traffic to its normal condition, that is, the westbound direction through the stretch of track shown. The operator at location B therefore closes push-button contact 19, associated with tratc lever SV, to initiate the action, previously described, to energize the buzzer llBZ and the indication lamp lek at location 'A. This signals the operator at A to initiate the necessary action to restore the tran'ic direction to nornal. The operator at B immediately opens contact 19 or allows it to open. Meanwhile, the operator at location A moves traffic lever 1V to the reverse indicating or locking position D. To do so, he must also release the spring latch, closing Contact 16, which as previously described will cause an indicationA to apear at location B by energizing buzzer SBZ and lamp Sek.

Assuming that the occupancy and route locking conditions are proper, the closing of contact 1S of lever 1V completes the circuit for energizing lock magnet 1M, so that lever 1V may be moved at once to the opposite extreme position, that is, the normal position N, and the spring latch released. lt is to be noted that it the cross-` over at location A is reversed, the occupancy of section 1T will not prevent the reversal of traic direction. A Contact 43 of the switch contactor associated with switch 1W, which is closed only when switch 1W is reversed, bypasses contact 33 of relay lTR to allow the traic locking circuit to be completed under these special conditions. When lever 1V is moved to its normal position, the open ing of contact l5 again interrupts the energizing circuit for lock magnet 1M, which releases locking dog 12 to prevent the return of lever 1V to its reverse position. Also, the opening of spring latch contact 16 interrupts the circuits for buzzer SBZ and lamp Sek.

Informed by the absence of the buzzer and the lamp indications that the operator at A has moved lever 1V to its norm-al position, the operator at B now moves lever SV to its normal position. This interrupts, at contact 18 of y relay SRFL. This circuit is otherwise completed over iront contact 14 of lever 1V, when it is moved to its normal position, and the trac locking circuit as previously traced including back contact 36 of relay SNFS. When relay SRFL picks up, with relay SNLP already having closed its front contacts, a circuit is completed for energizing relay SNFS. This circuit includes front contact 2d of relay SRFL and front contact 2S of relay SNLP. Relay SNFS picks up, and the opening of its back contact 3l interrupts the stick circuit for relay SRFS. Since the energizing circuit for this relay is already open, reverse trame stick relay SRFS releases and closes its back con- I tact 26 to complete the stick circuit for relay'SNFS, as

previously traced... ,The occupancyrand route locking check ofthetstretchnf railwaytrack is accomplished when relay SRFL is energized, since the traic locking circuit between the two locations must be complete in order to energize this reverse traic locking relay. The opening of back contact 36 of relay SNFS, when this relay picks up, interrupts the circuit for relay SRFL, and the closing of front contact 36 of relay SNFS completes the Vcircuit previously traced for energizing the normal traic locking relay SNFL, which then picks up. Relay SRFL is provided with a resistor co-nected in multiple with the relay winding to give the relay a slow release characteristic so that its front contacts will remain closed to bridge the time until the stick circuit for relay SNFS is completed.

When relay SNFS picks up and then is held up by itsstick circuit, trafc is once again established in the normal direction. The closing of front contact 38 of relay SNFS again completes the circuit, further controlled by the operation of lever 6V'to its L position, to energize the control circuits for the signals 6L. Under these conditions, the operation of lever 1V to its normal indicating or locking position B, while it would interrupt the circuit for energizing relay SNFL, cannot affect the indication displayed by signals 6L, since relay SNFS is held energized by its stick circuit. Likewise, the operation of trac lever SV to its reverse position will deenergize relay SNLP, but since relay 6XS would be energized with any one of the signals 6L cleared, the clos-ing of contact 18 of relay SV cannot energize relay SRLP. Thus the operation of the free lever SV under these conditions cannot aiect the indication displayed by signal 6L.

Referring now to Pig. 2, there is shown therein a second form of the circuit arrangement embodying our invention in which the two tralic stick relays of Fig. l are now replaced by a single traic stick relay, the relay SFS, which, as previously discussed, is of the double winding, magnetic stick type. In Fig. 2, only a portion of the circuit arrangement suicient to understand its operation as embodying our invention is shown. In other Words, the trallic locking circuit extending between locations A and B is shown with a contact of the tratlic stick relay SFS inserted in this circuit. Also, the energizing circuits for the trat-Tic stick relay SFS are shown. The remainder of the circuit arrangement is identical with the circuits shown in Fig. 1, and it is believed that a description of the two circuits shown in Fig. 2, taken in connection with the previously discussed operation of the circuits of Fig. l, will provide complete understanding of the second form of our invention.

As shown in Fig. 2, the circuits are in their normal condition, that is, with normal or westbound traflic established. Under these conditions, the normal trati'c locking relay SNFL is energized through the traic locking circuit, which extends from terminal LB at contact`14 of lever 1V at location A over front contacts 33, 34, and 3S of relays lTR, TR, and SWS, respectively, normal contact 44 oi relay SFS, and the winding of relay SNFL to terminal LN. Both of the energizing circuits for relay SFS are open under these normal conditions. However, since this relay is of the magnetic stick type, its contacts remain in the position to which they were last operated by current ilowing through either winding of the relay. As will appear shortly, the establishment of normal traffic causes current to flow in the direction of the arrow through the lower winding or this relay, closing normal contacts, which then remain closed until further change in the traic direction occurs.

in order to change the established traic to the reverse direction, the actions of the operators at the two locations are identical with those previously described in connection with the circuit arrangement of Fig. l. When lever 5V is moved to its reverse position, relay SNLP is deenergized and releases and relay SRLP, providing the conditions are proper, is lenergized by the closing of contact 18 of lever 5V.,Y As Ibefore,,the normal traine locking releyeNEL is..rn'evidedfsvithr Slis'htlyrslvtirelsase ,Char- 1 1 acteristics by the resistor connected in multiple with the relay winding, so that its front contact 28 remains eiosed to bridge this transition period. Thus the `closing of front contact 29 of relay SRLP completes a circuit for energizing the upper winding of relay SFS. This circuit extends from terminal B over front Contact 28 of relay SNFL, front contact 29 of relay SRLP, and the upper winding of relay SFS to terminal N. It is obvious that the fiow of current in this circuit is in a direction opposite to that of the arrow in the upper winding so that relay SFS operates its armature so as to close reverse contacts. The lock magnet 1M at location A is now energized by the circuit extending from terminal LB at location B over back contact 37 of relay SNLP, reverse contact 44 of relay SFS, front contacts 35, 34, and 33 of relays SVJS, STR, and 1T R, respectively, to assure that conditions are proper for a trafiic reversal, contact 15 of lever 1V, and the winding of the lock magnet 1M to terminal LN. With lock magnet 1M energized, lever 1V can then be moved to its extreme reverse position, thus establishing reverse traflic as previously described.

in order to restore trafiic to its normal direction, the actions of the operators are again identical with those previously described. With relay SFS occupying its reverse position, the energizing of relay SNLP upon the closing of contact 17 of lever 5V causes the circuit to be completed to energize reverse trafiic locking relay SRFL. This circuit extends from terminal LB at Contact 14 of lever lV 'at location A, and includes the previously men tioned front contacts 33, 34, and 35, and reverse contact 44 of relay SFS, front contact 37 of relay SNL?, and the winding of relay SRFL to terminal LN. Relay SRFL picks up, and the closing of its front contact 24 completes a circuit for energizing the lower winding of relay SFS. It is to be noted at this time that the circuit for energizing the upper winding is open at both front contact 28 ot' relay SNFL and front contact 29 of relay SRLP. The circuit for the lower winding of relay SFS, which includes front Contact 24 of relay SRFL and front contact 25 of relay SNLP, obviously causes current to iiow through the lower winding in the direction of the arrow. Thus ener* gized, relay SFS operates its armature to the normal position, closing normal contact 44. The trafiic locking circuit previously described is now transferred from relay SRFL to relay SNFL, this circuit being as previously traced except it now includes normal contact 44 of relay EFS and the winding of relay SNFL. Relay SRFL, thus deenergized, releases to open its front contact 2d interrupting the energizing circuit for the traffic stick relay, which, however, remains with its contacts in their normal position. it is to be noted, under this form of our invention, that the control circuits for signal 6L would be carried over a normal contact of tratiic stick relay SFS, so that the signals could be cleared only when traflic is established in the normal direction.

it is thus to be seen that by using either form of the traf'c control apparatus embodying our invention that several advantages are possible. There is an economic `advantage in that an existing traffic locking circuit between two locations can be re-used with a minimum amount of change at the location at which the modernization program is undertaken, that is, at the location in which the free lever replaces the mechanically locked lever. No change is necessary at the location at which the mechanically interlocked lever remains in service. An operating advantage is possible in that the mechanical lever remains locked and the free traffic lever, although free to move, cannot affect the indication displayed by any signal which has been cleared. Another operating advantage is that if the circuit is interrupted, operation can be restored by the operator without the necessity of calling a maintainer. Another advantage is that the traffic locking circuit between the two locations may be of a single wire and common type, that is, a single-break line circuit as shown, and may also, if desired, be a doublebreak line circuit.

Although we have herein shown and described but two forms of railway trafiic control apparatus embodying our invention, it is to be understood that various changes and modifications may be made therein within the scope of the appended claims with departing from the spirit and scope of our invention.

Having thus described our invention, what we claim is:

i. in combination with a stretch of railway track extending between a first and a second location, a wayside signal at each location to govern trafiic movements entering said stretch, and a traffic locking circuit comprising a single pair of conductors extending between said locations and responsive to traf'ric occupying said stretch; tratlie controlling apparatus for establishing trafiic through said stretch in a first or a second direction, said trafiic controlling apparatus comprising a first trafiic control means at said first location and a .second trafiic control means at said second location, said first and said second traiic control means being interlccked through said traffic locking circuit, said first control means being operable to a first position and to a second position corresponding to said first and said second trafiic direction respectively and including a lever lock means which when energized permits the operation of said first control means between said tirst and said second position; said second control means including a trafhc locking means, a trafhc stick means, and a manually operable trafiic direction relay means, each said means being operable to a first condition and to a second condition corresponding to said first and said second trafiic direction respectively; a circuit arrangement to operate said trafiic locking means to its first or its second condition to indicate that the established traffic direction may be changed to the opposite direction, said circuit arrangement including said traffic locking circuit and a contact closed when said first control means is in its first position, said circuit arrangement further being controlled respectively by said traffic stick means in its first condition or by said stick means in its second condition and a first condition contact of said direction relay means; a first circuit to operate said traflic stick means to its first condition to establish trafiic in said first direction and to permit the entering signal at said second location to be cleared, said first circuit including a first condition contact of said direction relay means and being controlled by said trafiic locking means in its second condition, a second circuit to operate said traffic stick means to its second condition to establish traiic in said second direction7 said second circuit including a second condition contact of said direction relay means and being controlled by said traffic locking means in its first condition, another circuit arrangement to energize said lever lock means to permit said first control means to be operated to its second position to permit the entering signal at said first location to be cleared, said other circuit arrangement including said trafiic locking circuit and a second condition contact of said direction relay means and being controlled by said trafiic stick means in its second condition.

2. In combination with a stretch of railway track, a first manually operable traffic control lever associated with a first end of said stretch, said first lever having a normal and a reverse extreme position and a normal and a reverse locking position between the extreme positions, a lock for said first lever which when energized releases said first lever for movement between said extreme positions and which when deenergized locks said first lever against movement past said normal or said reverse locking positions, a second manually operable traffic control lever associated with the opposite end of said stretch and having a normal and a reverse position, a normal and a reverse traffic locking relay, a normal and a reverse traffic stick relay, a single control channel between said end locations, an energizing circuit for said normal trafiic stick relay controlled by said second traffic lever in its normal position and including a front contact of said reverse traffic locking relay, an energizing circuit for `said reverse traffic stick relay controlled by said second traffic lever in its reverse position and including a front contact of said normal traffic locking relay, a stick circuit for each trafiic stick relay including a back contact of the opposite direction traffic stick relay,a first circuit including said control channel and a front contact of said normal traffice stick relay and controlled by said first trafiic lever in its normal position for energizing said normal trafiic locking relay, a second circuit including said channel and a back contact of said normal traffic stick relay and controlled by said second trafhc lever in its reverse position to energize said lock to permit movement of said first lever between extreme positions, and a third circuit including said channel and said back contact of said normal traffic stick relay and controlled by both traffic levers in their normal positions to energize said reverse traffic locking relay.

3. In combination with a stretch of railway track over which trame moves in a normal and a reverse direction, a first trafiic control lever associated with a first end of said stretch, said first lever being operable to a normal and a reverse extreme position and to a normal and areverse locking position between the extreme positions, a lock for -said first lever which permits said rst lever to move between said extreme positions only when said lock is energized, a second traffic control means associated with the other end of said stretch, said control means being operable to a normal position and to a reverse position, a single traffic control channel extending between the ends of said stretch and responsive to traffic occupying said stretch, a normal and a reverse traffic locking relay, a trafiic stick relay means operable to a normal condition and to a reverse condition, a first circuit to operate said stick relay means to its normal condition, said first circuit including a front contact of said reverse trafiic locking relay and a normal position contact of said traffic control means, a second circuit to operate said stick relay means, to its reverse condition, said second operating circuit including afront contact of said normal trafiic locking relay and a reverse position contact of said traffic control means, said traffic stick relay means establishing traffic in the direction corresponding to its operated condition, said stick relay means holding in either condition until operated to the other condition, a first control circuit to energize said normal tramc locking relay including said control channel and a normal condition contact of said `stick relay means and being controlled by said first lever in its normal position; a second control circuit to energize said reverse tra'ic locking relay including said control channel, a reverse condition contact of said stick relay means, and a normal position contact of said traffic control means, and being controlled by said first lever in its normal position; and a third control circuit to energize said lock to permit movement of: said first lever from one extreme position to the other, said third control circuit including said control channel, a reverse condition contact of said stick relay means, and a reverse position contact of said trafic control means, and being controlled by said first lever in its normal or reverse locking position.

4. Railway traffic controlling apparatus in combination with a stretch of track extending between a first and a second location, a trafiic governing signal at each location for governing traffic into said stretch and a traffic locking circuit comprising a single pair of conductors extending between said locations and responsive to trafiic occupying said stretch; said apparatus including a first trafc lever at said first location operable to a normal and a reverse extreme position and having a normal and a reverse locking position intervening between said extreme positions, a lock for saidfirst lever which when energized releases said first lever for movement between said extreme positions and which when deenergized locks said first lever against movement past said normal or said reverse locking positions, a second traffic lever at said second location operable to a normal and a reverse position at any time, a normal and a reverse traffic locking relay and a normal and a reverse traffic stick relay at said second location, each trafiic stick relay when energized establishing trafiic direction through said stretch in the corresponding direction, an energizing circuit for each traic stick relay including a front contact of the opposite traffic locking relay and controlled by said second traffic lever in the corresponding position, a stick circuit for each traffic stick relay including a back contact of the other stick relay, an energizing circuit for said normal traic locking relay including said traffic locking circuit and a front contact of said normal traffic stick relay and controlled by said first lever in its normal position, an energizing circuit for said reverse traffic locking relay including said trafiic locking circuit and a back contact of said normal traffic stick relay and controlled by both said levers in their normal positions, an energizing circuit for said lock including said traffic locking circuit and said back contact of said normal trafiic stick relay and controlled by said second lever in its reverse position and by said first lever in its normal or reverse locking position, a control means for the entering signal at said first loca tion effective only when said first lever is in its corresponding traffic position, and other control means for the entering signal at said second location effective only when the traffic stick relay for the corresponding direction is energized.

5. In combination with a stretch of railway track extending between a first and a second location, a wayside signal at each location to govern trafiic movements entering said stretch, and a traffic locking circuit comprising a single pair of conductors extending between said locations and responsive `to traffic occupying said stretch; traffic controlling apparatus for establishing traffic through said stretch in a first or a second direction, said traffic controlling apparatus comprising a first traffic control lever at said first location operable to a first and a second extreme position corresponding to said first`and said second traffic direction respectively and having a rst and a second intermediate locking position between the eX- treme positions, a lock for said first lever which when energized releases said first lever for movement between its extreme positions and which when deenergized locks said first lever from movement beyond said first or said second locking positions,'a second trafc control lever at said second location operable at any time to a first and a second position corresponding to said first and said second traffic direction respectively, a first and a second traffic locking relay at said second location, a traffic stick relay means at said second location operable to a first condition and to a second condition to establish traffic in said first and said second direction respectively, a first and a second energizing circuit to operate said stick relay means to its first and its second condition respectively, said first energizing circuit including a front contact of said second trafhc locking relay and controlled by said second lever in its first position, said second energizing circuit including a front contact of said first traffic locking relay and controlled by said second lever in its second position, said stick relay means holding in a particular operated condition until the energizing circuit is completed to operate the relay means to its other condition, an energizing circuit for said first traffic locking relay including said trafiic locking circuit and a first condition contact of said stick relay means and controlled by said first lever in its first position, an energizing circuit for said second traffic locking relay including said traffic locking circuit and a second condition contact of said stick relay means and controlled by both said levers in their first positions, an energizing circuit for said lock including said trafiic locking circuit and a second condition contact of said stick relay means and controlled by said first lever in its first or second locking position and by said second lever in its second position, a control means for the entering signal at said first location effective to clear the signal only if said first lever is in its second position, and another control means for the entering signal at said second location effective to clear the signal only if said stick relay means is operated to its first condition.

6. ln combination with a stretch of railway track eX- tcnding between a first and a second location, a wayside signal at each location to govern traffic movements entering sai-:l stretch, and a traffic locking circuit comprising a single pair of conductors extending between said locations and responsive to trafiic occupying said stretch; trafiic controlling apparatus for establishing trafic through said stretch in a first or a second direction, said traffic controlling apparatus conjrising a first trafiic control lever et said location operable to a first and a second extreme position corresponding to said first and said second trafiic direction respectively and having a first and a second intermediate locking position between the extreme positions, a lock for said first lever which when energized releases said first lever for movement between its eX- treme positions and which when deenergized lockssaid first lever from movement beyond said first or said second locking positions, a second trafiic control lever at said second location operable at any time to a first and e. second position corresponding to said first and said second traffic direction respectively, a first and a second trafiic locking relay at said second location, a traffic stick elay of the magnetic stick type having two windings at said second location, said stick relay operable to a first position by current in a normal direction in either Winding and to a second position by current in a reverse direction in either winding, said first and said second positions establishing traffic in said first and said second directions respectively, a first energizing circuit for said stick relay including a front contact of said second traffic loci-Ling relay and a first winding of said stick relay, said first energizing circuit further being controlled by said second lever in its first position and being arranged that current flows in the normal direction in said first winding, a second energizing circuit for said stick relay including a front contact of said first traic locking relay and second winding of said stick relay, said second energizing circuit further being controlled by said second lever in its second position and being arranged that current flows in the reverse direction in said second winding, an energizing circuit for said first traffic locking relay including said tratiic locking circuit and a first position contact of said stick relay and controlled by said first lever in its first position, an energizing circuit for said second traffic locking relay including said traffic locking circuit and a second position contact of said stick relay and controlled by `both said levers in their first positions, an energizing circuit for said lock including said traffic locking circuit and a second position contact of said stick relay and controlled by said first lever in its first or second locking position and by said second lever in its second position, a control means for the entering signal at said first location effective to clear the signal only if said first lever is in its second position, and

another control means for the entering signal at said second location effective to clear the signal only if said stick relay is operated to its first position.

7. ln combination with a stretch of railway track extending between a first and a second location, a wayside signal at each location to govern traiiic movements entering said stretch, and traffic locking circuit comprising a single pair of conductors extending between said locations and responsive tctr:` ne occupying said stretch; traffic controlling apparntus for establishing traffic through said stretch in a first or a second direction, said traffic controlling apparatus comprising a first traffic control means at said first location and a second tramo control means at said second location, said first and said second traffic control means being interlock d through said traffic locking circuit, said first control means including a first traffic lever, a lock for said first lever, and a control arrangement for said rst entering signal; said first lever having a first and a second extreme position and a first and a second locking position between said extreme positions, movement of said first lever between said extreme positions being permitted only when said lock is energized, movement between either extreme position and the corresponding locking position being permitted at any time, said firstv signal control arrangement becoming effective to clear that signal only when said rst lever occupies its second extreme position; said second control means including a second traffic lever, a first and a second traffic locking relay, a trafiic stick relay means, and a control arrangement for the second entering signal; said second lever being operable at any time to a first and a second position, said stick relay means being operable to a first condition and a second condition, a first and a second energizing circuit edective to operate said stick relay means to its first an its secon-d condition respectively, said first energizing circuit including a front Contact of said second trafic loef-:ing relay and controlled by said second le er in its first position, said second energizing circuit inciuding a front contact cf said first traffic locking relay and controlled by said second lever in its second position; an energizing circuit for said first trafiic locking relay including said traffic locking circuit and a first condition contact of said stick relay means and controlled by said first lever in its first extreme position, an energizing circuit for said second traffic locking relay including said traffic locking circuit and a second condition contact of said stick relay means and controlled by said first lever in its first eXtreme position and by said second lever in its first position, an energizing circuit for said first lever lock including said trafic locking circuit and a second condition contact of said stick relay means and controlled by said second lever in its second position and by said first lever in its first or second locking position, said second signal. control arrangement becoming effective to clear that signal only when said traffic stick relay means is in its first condition.

References Cited in the file of this patent UNITED STATES PATENTS 2,227,610 Vanhorn Jan. 7, 1941 

